Helical stent

1. A self-expanding stent graft, comprising:

a tubular graft having a proximal end, a distal end, and a length from the proximal end to the distal end;

a single elastic helical wire disposed on the graft and having first and second ends, the single elastic helical wire comprising a zig zag pattern of angular struts and bends connecting circumferentially adjacent angular struts, wherein the single elastic helical wire is preformed and set into a continuous helical cylindrical pattern prior to attachment to the tubular graft to comprise a tubular stent in a stressed relaxed state, and

wherein the tubular stent is disposed along the length of the tubular graft and in the stress relaxed state;

wherein all of the angular struts are of the same length;

wherein longitudinally adjacent turns of the stent are free of any longitudinal connectors between them;

wherein circumferentially adjacent bends define a pitch angle of the helical cylindrical pattern with respect to a plane transverse to the axis of the stent;

wherein the bends and the angular struts define bisecting lines extending through the bends and between circumferentially adjacent angular struts, and the bisecting lines are angled from about 5° to about 20° with respect to a longitudinal axis extending through the helical cylindrical pattern of the stent,

wherein longitudinally adjacent angular struts and bends are spaced apart from each other in the wire's relaxed state;

wherein the stent is configured to change in length as much as 50% to accommodate shape changes in a patient's body;

and

wherein the stent graft is configured to bend one hundred and eighty degrees without kinking.

2. The stent graft of claim 1 , wherein the ends of the single wire are formed into circular, non-helical rings having a zig zag pattern of struts and bends, wherein the struts in the circular, non-helical rings are of unequal lengths.

3. The stent graft of claim 1 , wherein the pitch angle is from about 5° to about 20°.

4. The stent graft of claim 3 , wherein the pitch angle and the angle of the bisecting lines is the same.

5. The stent graft of claim 4 , wherein longitudinally adjacent bends are circumferentially offset from each other so that the bends are helically arranged relative to each other.

6. The stent graft of claim 5 wherein longitudinally adjacent bends are nested within each other.

7. The stent graft of claim 4 wherein longitudinally adjacent bends are nested within each other.